Research On The Stability Of High-Speed Railway CWR Under An Earthquake

With the development of high-speed railway,CWR have become the best choice for track structure.Due to its location in two major seismic belts,China is an earthquake-prone country,and the track line inevitably passes through the seismic belt.At present,the seismic research of railway engineering focuses on the subgrade,bridge and tunnel structure,and there is little research on the impact of earthquake on the track structure.Under the action of earthquakes,the CWR will produce lateral deformation and affect its stability.Therefore,it is necessary to analyze the bending deformation of the ballasted track and the ballastless track under the earthquake and rail temperature force.The stability after the earthquake was evaluated.This paper has conducted the following aspects of research:(1)In this paper,the seismic response time history equation and solution method of the track structure is proposed by the dynamic time history analysis.The type of ground motion records,the input method of these,and the parameters of the track model reasonably are selected,and finite element software is used to establish a finite element analysis model of the CWR of high-speed railway ballasted track and CRTS Ⅲ ballastless track under earthquake.(2)For the type Ⅲ sleepers ballasted track CWR,the relationship between seismic degrees and the deformation of the track under the earthquake is analyzed,and which presents that the deformation of the rail is mainly lateral,and when the seismic intensity is 7 degrees and below,the deformation of the straight track is generally less than 2mm,elastic vibration,and there is no instability.If 8 degrees and above,the track starts to slip and deform,and the line will be unstable.(3)For type Ⅲ sleepers ballastless track CWR under the action of earthquake,the temperature of the rail and the resistance of the track bed play a significant role on the stability of the ballasted track CWR of the high-speed railway.As the rail temperature increases,the lateral displacement of the track increases continuously,showing a non-linear growth;when the temperature change and seismic intensity reach a certain level,the line will undergo plastic deformation that will eventually lead to instability and cause line damage.For straight track and 3000 m radius track,7 degrees of intensity,when the rail temperature rise exceeds 50℃,40℃ respectively;when 6 degrees of intensity,the rail temperature rise exceeds 50℃ respectively;5 degrees of intensity,the rail temperature rise exceeds 60℃,the track will be deformed,affecting the stability of the CWR.The reduction of the lateral resistance of the CWR ballasted bed under the earthquake will greatly make the lateral deformation of the track increase,and as the temperature increases,which is more obvious,and the lateral displacement of the rail increases nonlinearly.For 600 m and 800 m radius curve tracks,7 degrees of intensity,temperature rise exceeds 30°C,the stability of the CWR will be affected.(4)A study on the stability of the CWR of CRTS Ⅲ slab ballastless track under the earthquake.Studies have shown that under the action of earthquakes,the deformation of ballastless track structure is mainly lateral.7 degrees of intensity,under the condition of no temperature rise,the displacement and stress response of the straight track structure also increase nearly twice as the intensity increases by one degree.Considering the temperature rise of the rails,7 degrees of intensity or less,the lateral displacement values of the rails,track slabs,and base slabs of straight track and 3000 m radius track increase nonlinearly by increasing rail temperature,and the lateral deformations are all elastic deformations,and the displacements are all within 2mm,and the track is not unstable and damaged.Figure 48,table 24,reference72.